Demo's

Living or Non-Living? Demo

Tell the class that you are going to do two demonstrations. You want them to make close observations and to be prepared to explain what they saw happen during each demonstration.

Demonstration 1

1. Fill the baking dish with about 1/2 inch of water and place it on the overhead projector. Use 2 opened file folders as a screen to block students' view of the baking dish sitting on the projector.
2. Out of view of the students, behind the screen made from the file folders, sprinkle enough pepper onto the surface of water so that it is pretty well covered. Turn on the overhead projector. Your students will see the paper as shadows on the screen.
3. Place a drop of liquid dish soap on the surface of the water. Your students should see the shadows of the pepper flakes immediately move away from the soap toward the sides of the dish.
4. Ask students to explain what they observed happening and what they think the little things floating on the water are. Why did they move away? Do they think the little things are alive?

Demonstration 2
Thoroughly rinse out the dish before beginning the second demonstration.

1. Place the dish on the overhead and fill it with 1/2 inch of water. Again use the folders to screen your actions from you students.
2. After the water has stopped moving, place a shape similar to the one shown below cut from oaktag, on the surface of the water.
3. Place a drop of liquid dish washing soap in the center hole. Your students will see the shape move quickly across the water.
4. Discuss with the class what happened to the shape. Why do they think the shape moved? Is the shape alive?
5. Explain to the class that the demonstrations did not have any living things in them. Show them the pepper, oaktag shape, and soap. Explain that the pepper and the shape moved away from the soap because it broke the surface tension of the water. Not everything that moves is alive. Have the class list things that move that are not alive.